Losing your marriage, the relationship you thought you had, the future you thought you had causes unbelievable grief and pain. I'm so sorry you're going this this. I hate to tell you that it can takes YEARS to get over it. It'll be 2 years in May since my life blew up and it's still there. But, it's nothing like it was. There are days I am still sad. There are things that still make me angry. I really had a hard time over the holidays. But, I can promise you is does get easier.
The only advice I can give you is to allow yourself to have your feelings. Counseling does help. For the sake of your children though, be very careful not to be critical of their mother. I was told that "as long as you treat your ex with respect around the kids, the kids will be fine and your relationship with them will be fine", and it was so true. I never stooped to the level my ex did. I'm not saying that it didn't take a long time for my kids to recover, but my relationship with them is strong. In the long run they haven't forgiven their dad for how he talked to them about me after the divorce.
Take care......